1. Field of the Invention
This invention is directed to coating compositions, in particular to a clear coating composition used as a clear coat over a color coating or base coating of a motor vehicle that has improved mar and acid etch resistance.
2. Description of the Prior Art
Acid rain and other air pollutants have caused problems of water spotting and acid etching of finishes used on automobiles and trucks. The finish of choice presently being used on the exterior of automobiles and trucks is a clear coat/color coat finish in which a clear coating is applied over a color coating or base coating which is pigmented to provide protection to the color coat and improve the appearance of the overall finish such as gloss and distinctness of image. Another problem is mar resistance of the clear coat. Marring of the finish can be caused by mechanical washing procedures used in a typical commercial car wash or by other mechanical marring of the finish.
A number of clear coatings containing acrylosilane polymers have been used as clear coats as shown in Hazan et al U.S. Pat. No. 5,066,698 issued Nov. 19, 1991, Nordstrom et al U.S. Pat. No. 5,532,027 issued Jul. 2, 1996 and Lewin et al U.S. Pat. No. 5,684,084 issued Nov. 4, 1997. However, none of the compositions shown in the above patents have the necessary combination of properties including costs that are desired for an automotive OEM (original equipment manufacturing) clear coating composition.
There is a need for an OEM clear coating compositions that will form finishes that are resistant to acid etching and water spotting caused by acid rain and are resistant to marring.